Hinge device for storage cases and storage case having the same

ABSTRACT

A hinge device for storage cases to hingedly connect a case body and a door. The hinge device includes a housing fixed to one of the case body and the door, first and second hinge shafts rotatably attached to opposite ends of the housing, respectively, such that the first and second hinge shafts are fixed to the other of the case body and the door, a cam driving unit disposed at the first hinge shaft in the housing, and a torsion spring having one end fixed to the second hinge shaft and the other end fixed in the housing such that the rotation resistance of the door is increased when the door is closed, and the torsion spring is returned to its original state when the door is opened.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2005-0040390, filed on May 16, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hinge device for storage cases and a storage case having the same. More particularly, to a hinge device for storage cases that is capable of enabling a door to be smoothly closed while the structure of the hinge device is simplified, and a storage case having the same.

2. Description of the Related Art

Generally, a conventional Kimchi storage case is a storage case constructed such that the top of a case body can be opened and closed. Specifically, a door is hingedly attached to the top of the case body such that the door can be opened and closed.

The conventional Kimchi storage case includes a case body having a storage compartment opened at the top thereof, a door to open or close the top of the storage compartment, and a hinge device disposed between the case body and the door to connect the case body and the door such that the door can be opened and closed in a hinged fashion.

An example of conventional hinge devices is disclosed in Korean Registered Utility Model Publication No. 20-0298042, which provides a hinge device for Kimchi storage cases including a cylindrical housing fixed to the top of a storage case body to connect the rear end of a door and the storage case body, two hinge units mounted in opposite ends of the housing to hingedly connect opposite sides of the rear end of the door with the opposite ends of the housing, and shafts extending from the hinge units such that the shafts are connected to the opposite sides of the rear end of the door.

In the conventional hinge units for storage cases with the above-stated construction, however, the housing, which is fixed to the case body, and the two hinge units, which are mounted in the opposite ends of the housing, are separately manufactured. Also, each hinge unit includes a hinge driving part, which is disposed in an additional small housing. Consequently, there are many components constituting the hinge device, and therefore, the manufacturing costs of the hinge device are increased. In addition, the two hinge units are individually manufactured, and then the hinge units are mounted in the opposite sides of the housing, and therefore, the manufacturing process is complicated. Furthermore, the door is heavy in comparison to the shock-absorbing function of the hinge device within a closing section, and therefore, an impact force is high when the door is closed.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a hinge device for storage cases that is capable of enabling a door to be more smoothly closed while the structure of the hinge device is simplified and a storage case having the same.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

These and/or other aspects of the present invention are achieved by providing a hinge device for storage cases to hingedly connect a case body and a door, the hinge device including a housing fixed to one of the case body and the door, first and second hinge shafts rotatably attached to opposite ends of the housing, respectively, such that the first and second hinge shafts are fixed with the other of the case body and the door, a cam driving unit disposed at the first hinge shaft in the housing, and a torsion spring having one end fixed with the second hinge shaft and the other end fixed in the housing such that the rotation resistance of the door is increased when the door is closed, and the torsion spring is returned to an original state thereof when the door is opened.

The cam driving unit includes a first cam disposed at the first hinge shaft, a moving member including a second cam disposed opposite to the first cam, and a compression spring to elastically push the moving member toward the first cam.

The hinge device further includes a fixing member disposed in the housing at the second hinge shaft side, wherein the rotation of the fixing member is prevented, to fix an end of the torsion spring at a side opposite to the second hinge shaft.

The hinge device further includes a connection hole formed at one end of the housing at a side of the second hinge shaft, a rotation preventing pin inserted in the connection hole, and a catching part formed at the second hinge shaft in the housing such that the catching part is caught by the rotating preventing pin to prevent the rotation of the second hinge shaft.

The first and second cams include valley-shaped and crest-shaped cam surfaces, the cam surfaces including opening guide surfaces formed at an oblique angle and closing guide surface formed substantially horizontally

The hinge device further includes a leakage preventing member disposed at the outside of the first or second cam to prevent lubricant applied to the respective cam surfaces from leaking out of the cams.

The hinge device further includes a shaft disposed in the housing between the first hinge shaft and the second hinge shaft, the shaft extending in a longitudinal direction of the housing such that opposite ends of the shaft are mounted to the hinge shafts, respectively, the shaft being inserted through the cam driving unit and the torsion spring.

Opposite ends of the shaft are rotatably mounted with the hinge shafts, respectively.

The opposite ends of the shaft are mounted to the hinge shafts, respectively, while the rotation of the shaft is restricted.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is an exploded perspective view illustrating an outer appearance of a Kimchi storage case, to which the present invention is applied, and a door attachment structure of the storage case;

FIG. 2 is a sectional view illustrating an inner construction of the Kimchi storage case, to which the present invention is applied, and the door attachment structure of the storage case;

FIG. 3 is an exploded perspective view illustrating a construction of a hinge device for storage cases according to a first embodiment of the present invention;

FIG. 4 is a sectional view illustrating the construction of the hinge device for storage cases according to the first embodiment of the present invention when the door is closed;

FIG. 5 is a sectional view illustrating the construction of the hinge device for storage cases according to the first embodiment of the present invention when the door is opened;

FIG. 6 is a perspective view illustrating a moving member of the hinge device for storage cases according an embodiment of the present invention;

FIG. 7 is a development view illustrating the construction of first and second cams of the hinge device for storage cases according to an embodiment of the present invention when the door is opened;

FIG. 8 is a development view illustrating the construction of the first and second cams of the hinge device for storage cases according to the present invention when the door is closed;

FIG. 9 is an exploded perspective view illustrating a connection structure of a rotation preventing pin connected to a second hinge shaft of the hinge device for storage cases according to an embodiment of the present invention;

FIG. 10 is an exploded perspective view illustrating the construction of a damping unit of a hinge device for storage cases according to a second embodiment of the present invention;

FIG. 11 is an exploded perspective view illustrating the construction of the damping unit of the hinge device for storage cases according to the second embodiment of the present invention when a second elastic member is twisted;

FIG. 12 is an exploded view, in section, illustrating the structure of a hinge device for storage cases according to a third embodiment of the present invention; and

FIG. 13 is a sectional view illustrating the structure of the hinge device for storage cases according to the third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

The storage case illustrated in the following embodiments of the present invention is a Kimchi storage case. However, the present invention is not limited hereto, and may be applied to any type of storage case.

FIG. 1 is an exploded perspective view of a Kimchi storage case, to which the present invention is applied, and FIG. 2 is a sectional view of the Kimchi storage case, to which the present invention is applied. In FIGS. 1 and 2, the Kimchi storage case, which is made of an insulating material, comprises a case body 2 having a storage compartment 1 defined therein, the storage compartment 1 being opened at the top thereof, and a door 3 hingedly attached to a top of the case body 2 to open and close the top of the storage compartment 1.

At an outside of a liner 1 a of the storage compartment 1 are disposed an evaporator 1 b formed of a common refrigerant pipe to cool the storage compartment 1, a heater 1 c formed of a common electric heat wire to mature Kimchi stored in the storage compartment 1. At the lower part of one side of the case body 2 is formed a machinery compartment 4, which is separated from the storage compartment 1 and in which an compressor 4 a is mounted.

A rear end of the door 3 is hingedly attached to the top of the case body 2 such that the door 3 can be rotated in a hinged fashion by means of a hinge device 5. The hinge device 5 is fixed at a rear upper end of the case body 2. The hinge device comprises hinge shafts 10 and 20 disposed rotatably attached to the opposite ends thereof.

The door 3 is provided at opposite sides of the rear end thereof with connection parts 3 a, with which the hinge shafts 10 and 20 are connected. Covers 3 b are attached to the connection parts 3 a, respectively.

The hinge shafts 10 and 20 attached to the opposite ends of the hinge device 5 are disposed between the connection parts 3 a and the covers 3 b, respectively, such that the rotation of the hinge shafts 10 and 20 is restricted. In this way, the door 3 is hingedly connected to the case body 2.

In FIGS. 3-5, the hinge device 5 comprises a housing 30 forming an external appearance of the hinge device and connected with the top of the case body 2 of the Kimchi storage case, a pair of hinge shafts 10 and 20 rotatably attached to the opposite ends of the housing 30, each of the hinge shafts 10 and 20 having one end extending into the housing 30 and door connection parts 11 and 21, respectively, formed at the other end, which extends outward from the housing 30. The door connection parts 11 and 21 are fixedly connected with the connection parts 3 a of the door 3. Hereinafter, the hinge shafts 10 and 20 are referred to as a first hinge shaft 10 and a second hinge shaft 20.

The hinge device 5 further comprises a cam driving unit disposed in the housing 30 at the first hinge shaft side to provide a rotating force to the first hinge shaft 10 such that the door can be maintained opened or closed depending upon an opening angle of the door 3, and a damping unit disposed in the housing 30 at the second hinge shaft side to increase the rotation resistance of the door 3 when the door 3 is closed.

The housing 30 comprises a housing body 32 opened at opposite ends thereof and having a receiving space 31 formed in a longitudinal direction of the housing 30 to receive the cam driving unit and the damping unit, and a pair of covers 33 and 34 disposed at the opened ends of the housing body 32 to close the opposite ends of the housing body 32, the covers 33 and 34 having shaft insertion holes 33 a and 34 a formed at centers thereof such that the door connection parts 11 and 21 of the hinge shafts 10 and 20 can be inserted into the shaft insertion holes 33 a and 34 a, respectively. The covers 33 and 34 fixedly attached to the opposite ends of the housing body 32 by means of a plurality of fixing screws.

A fixing plate 35 is integrally formed with the housing body 32 such that the housing 30 can be fixed to the case body 2 of the Kimchi storage case by means of the fixing plate 35. The receiving space 31 is divided into a first receiving part 31 a, in which the cam driving unit is received, and a second receiving part 31 b, in which the damping unit is received.

Now, the structures of the first hinge shaft 10 and the cam driving unit will be described in detail. At the first hinge shaft 10, which extends into the first receiving part 31 a, is formed a cam shaft part 12 having a first cam 13 formed at the outer surface thereof. The cam driving unit comprises a moving member 40 movably fitted on the cam shaft part 12 while the rotation of the moving member 40 is restricted, the moving member 40 having a second cam 43 contacting the first cam 13, and a first elastic member 50 to push the moving member 40 toward the first cam 13. The first elastic member 50 is a compression spring.

In the first receiving part 31 a inside the moving member 40 is disposed a supporting member 60 to support the first elastic member 50. At one end of the supporting member 60 at the first elastic member side is formed a guide 61, which is inserted into the first elastic member 50 within a predetermined length. At the first hinge shaft 20 is formed a support protrusion 14 which is caught by the shaft insertion hole 33 a such that the support protrusion 14 is supported at the inside of the cover 33.

In FIGS. 6-8, the moving member 40 is moved along the inner surface of the first receiving part 31. The moving member 40 is provided at a center thereof with a through-hole 41, through which the cam shaft part 12 of the first hinge shaft 10 is inserted.

Inside the housing body 32 of the housing 30 at the first receiving part side is formed a guide rail 31 a-1 (as shown in FIG. 3), which extends a predetermined length in the longitudinal direction of the first hinge shaft 10 such that the moving member 40 can be smoothly moved while the rotation of the moving member 40 is restricted. At the moving member 40 is formed a guide groove 42, in which the guide rail 31 a-1 is engaged.

The second cam 43 is integrally formed with one side surface at the moving member 40, which is opposite to the first cam 13, such that the rotation of the first hinge shaft 10 is caused through the movement of the moving member 40. The first elastic member 50 is fitted on the cam shaft part 12 of the first hinge shaft 10 to push the moving member 40 toward the first cam 13. In this construction, a cam surface 44 (shown in FIG. 6) of the second cam 43 of the moving member 40 usually pushes a cam surface 15 (shown in FIG. 7) of the first cam 13 formed at the cam shaft part 12.

The cam surface 15 of the first cam 13 and the cam surface 43 of the second cam 43 are formed in a shape of a valley and a crest such that the cam surface 15 of the first cam 13 and the cam surface 43 of the second cam 43 are engaged with each other.

Specifically, the cam surfaces 15 and 44 of the first and second cams 13 and 43 have opening guide surfaces 15 a and 44 a formed at an oblique angle in a spiral direction such that, when the door 3 is opened more than a predetermined angle, the first hinge shaft 10 connected to the door 3 can be rotated in the door opening direction due to an elasticity of the first elastic member 50 pushing the moving member 40. When the door 3 is opened more than the predetermined angle, the rotating force of the door 3 in the opening direction is applied to the first hinge shaft 10, and therefore, the door 3 is maintained opened.

Also, the cam surfaces 15 and 44 of the first and second cams 13 and 43 comprise closing guide surfaces 15 b and 44 b formed in a rotating direction of the first hinge shaft 10 such that when the opening angle is below the predetermined angle in the course of closing the door 3, the first hinge shaft 10 connected with the door is rotated in the door closing direction by the weight of the door 2. When the closing guide surface 15 b of the first cam 13 and the closing guide surface 44 b of the second cam 43 are brought into contact with each other, the elasticity of the first elastic member 50 does not affect the rotation of the first hinge shaft 10, and therefore, the door 3 is closed by its own weight.

Alternatively, the cam surfaces 15 and 44 may not comprise the closing guide surfaces 15 b and 44 b, and therefore, the door 3 may be closed by its own weight in the state that the end of the opening guide surface 15 a at the closing guide surface 15 b and the end of the opening guide surface 44 a at the closing guide surface 44 b are supported by each other.

To accomplish smooth sliding between the cam surfaces 15 and 44 of the first and second cams 13 and 43, a lubricant, such as grease, is applied to the cam surfaces 15 and 44 of the first and second cams 13 and 43. At an outside of the second cam 43 is disposed a cylindrical leakage preventing member 70 to prevent the lubricant applied to the respective cam surfaces 15 and 44 from leaking out of the cams 13 and 43 (see FIGS. 3-5).

The leakage preventing member 70 is forcibly fitted on the second cam 43 such that the first cam 13 is received in the leakage preventing member 70 while the opening guide surface 15 a of the cam surface 15 of the first cam 13 is in contact with the opening guide surface 44 a of the cam surface 44 of the second cam 43. Alternatively, the leakage preventing member 70 may be fitted on the first cam 13 such that the second cam 43 is received in the leakage preventing member 70.

In FIGS. 3-5, the second hinge shaft 20 comprises a support protrusion 22, which is formed at an end opposite to the door connection part 21 extending into the second receiving part 31 b of the housing 30. The support protrusion 22 is caught by the shaft insertion hole 34 a of the cover 34 such that the support protrusion 22 is supported at the inside of the cover 34. A damping unit, which is disposed in the second receiving part 31 b of the housing 30, comprises a fixing member 80 configured to be supported by the supporting member 60 of the cam driving unit, a guide rod 90, having one end inserted into a center of the fixing member 80 and the other end rotatably inserted into a center of the second hinge shaft 20, to connect the fixing member 80 and the second hinge shaft 20, and a second elastic member 100 wounded on the guide rod 90, the second elastic member 100 having one end fixed to the fixing member 80 and the other end fixed to the second hinge shaft 20.

At centers of the fixing member 80 and the second hinge shaft 20 are formed a first insertion groove 81 and a second insertion groove 22 a, respectively, through which opposite ends of the guide rod 90 is inserted.

The second elastic member 100 is a torsion spring. However, it is not limited hereto, and may vary as necessary.

Inside the housing body 32 of the housing 30 at the fixing member side is formed a rotation preventing protrusion 31 b-1 (shown in FIG. 3), which extends a predetermined length in a longitudinal direction of the housing 30 such that the fixing member 80 is prevented from being rotated in the second receiving part. The fixing member 80 comprises a rotation preventing groove 82 in which the rotation preventing protrusion 31 b-1 is engaged.

The guide rod 90 guides the second elastic member 100. Unlike the illustrated embodiment, as an alternative, the guide rod 90 may be integrally formed either with the fixing member 80 or with the second hinge shaft 20. When the guide rod 90 is integrally formed with the fixing member 80 such that the second elastic member 100 can be twisted, it is required that an end of the second hinge shaft 20 be rotatably inserted into the second hinge shaft 20. When the guide rod 90 is integrally formed with the second hinge shaft 20, it is required that the guide rod 90 be rotated along with the second hinge shaft 20.

When the door 3 is hingedly rotated from the opened state to the closed state, the damping unit enables the rotation resistance generated by twisting stress of the second elastic member 100 to be transmitted to the door 3 via the second hinge shaft 20 such that the rotating speed of the door 3 is reduced, and therefore, the door 3 is smoothly closed.

When the door 3 is hingedly rotated from the closed state to the opened state, on the other hand, the damping unit enables the second hinge shaft 20 to be rotated in the door opening direction by the restoring force of the second elastic member 100, which returns the second elastic member 100 from the twisted state to the original state, such that the opening force of the door 3 is increased.

More specifically, the second elastic member 100 comprises a member body 101 to be wounded on the guide rod 90, and first and second fixing parts 102 and 103 formed at opposite ends of the member body 101. The first fixing part 102 is fixed at a first fixing groove 83 formed adjacent to the center of the fixing member 80, and the second fixing part 103 is fixed at a second fixing groove 22 b formed adjacent to the center of the second hinge shaft 20. While the door 3 is open, the second elastic member 100 is not twisted. When the door 3 is closed, on the other hand, the second elastic member 100 is twisted.

Consequently, when the door, which is open, is rotated in the door closing direction, the second hinge shaft 20 is rotated, and therefore, the second fixing part 103 of the second elastic member 100 is rotated along with the second hinge shaft 20. When the second hinge shaft 20 is rotated, the second elastic member 100 is twisted while the first fixing part 102 of the second elastic member 100 fixed to the fixing member 80 is maintained fixed. This twisting stress of the second elastic member 100 increases the rotation resistance of the door 3, and therefore, the door 3 is smoothly closed.

When the door, which is closed, is rotated in a door opening direction, on the other hand, the second hinge shaft 20 is rotated in the door opening direction by the restoring force of the twisted second elastic member 100, and therefore, the door is easily opened by even a small external force.

The hinge device 5 is mounted to connect the door 3 and the case body 2 more stably in the state that the door 2 is closed such that the door 3 is supported at the top of the case body 2. Consequently, the hinge device 5 is mounted in a state that the second hinge shaft 20 is rotated in a direction opposite to the door opening direction to twist the second elastic member 100. At this time, the second hinge shaft 20 is rotated in a direction opposite to the second elastic member returning direction by the restoring force of the second elastic member 100 twisted in the course of connecting the door connecting part 21 of the second hinge shaft 20 to the connection part 3 a of the door 3. As a result, it is difficult to connect the door connection part 21 of the second hinge shaft 20 to the connection part 3 a of the door 3.

In order to solve this problem, as shown in FIG. 9, a connection hole 34 b is formed adjacent to the shaft insertion hole 34 a of the cover 34 fixedly attached to one end of the housing 30 such that a rotating preventing pin 110 is inserted into the housing 30 through the connection hole 34 b. At the support protrusion 22 of the second hinge shaft 20 is formed a catching part 22 c, which is caught by the rotating preventing pin 110 inserted into the housing 30 through the connection hole 34 b such that the rotation of the second hinge shaft 20 is prevented.

When the second hinge shaft 20 is rotated in one direction such that the second elastic member 100 is twisted, the rotating preventing pin 110 is inserted into the housing 30 through the connection hole 34 b such that the catching part 22 c is caught by an end of the rotating preventing pin 110 inserted into the housing 30. As a result, the second hinge shaft 20 is not rotated in the second elastic member returning direction, and therefore, the second elastic member 100 is maintained twisted.

In the illustrated embodiment, the catching part 22 c comprises a shape of a groove, into which the end of the rotating preventing pin 110 is inserted. However, the shape of the catching part 22 c is not limited hereto. Thus, the catching part 22 c may be formed in one of other shapes so long as the catching part 22 c is caught by the rotating preventing pin 110. For example, the catching part 22 c may comprise a shape of a protrusion or a hole similar to the connection hole 34 b of the cover 34.

After the door connection part 21 of the second hinge shaft 20 is inserted into the connection part 3 a of the door 3, the rotating preventing pin 110 is removed from the cover 34 such that a connection of the cover 3 b and the connection part 3 a is disturbed by the rotating preventing pin 110, and then the cover 3 b is connected with the connection part 3 a. Consequently, after the connection of the door 3 and the case body 2 is completed, the second hinge shaft 20 can be rotated in one direction or the opposite direction according to the door opening or closing operation.

The operation of the hinge device for storage cases with the above-stated construction according to the present invention will be described hereinafter in detail.

When a user opens or closes the door 3 of the Kimchi storage case, the first and second hinge shafts 10 and 20 are rotated along with the door 3. At this time, the door 3 is easily opened or closed by a rotating force of the first hinge shaft 10 generated via the cam driving unit.

Specifically, when the first hinge shaft 10 is rotated, the first cam 13 mounted at the first hinge shaft 10 is also rotated. At this time, the moving member 40 is in a state of being forced to move to the first cam 13 by elasticity of the first elastic member 50, and the second cam 43 of the moving member 40 is in contact with the first cam 13. As a result, when the first hinge shaft 10 is rotated in the door opening or closing direction, the second cam 43 of the moving member 40 is moved in ta longitudinal direction of the first hinge shaft 10 to push the first cam 13 of the first hinge shaft 10. Consequently, the opening or closing of the door 3 is easily accomplished by the relationship between the friction force generated between the first cam 13 and the second cam 43 by the pushing force of the first elastic member 50 and the weight of the door 3.

More specifically, when the door 3 of the Kimchi storage case is opened more than the predetermined angle, and therefore, the door 3 is placed within the opening section shown in FIG. 2, the inclined opening guide surface 44 a of the second cam 43 and the inclined opening guide surface 15 a of the first cam 13 are brought into contact with each other, as shown in FIGS. 4 and 7. Thus, the second cam 43 of the moving member 40 is moved to the first cam 13 to push the opening guide surface 15 a of the first cam 13. Consequently, a rotating force is applied to the first hinge shaft 10 such that the first hinge shaft 10 can be rotated in the door opening direction, and therefore, the door 3 is easily opened. At this time, if the elastic force of the first elastic member 50 is appropriately controlled such that the rotating force applied to the first hinge shaft 10 such that the first hinge shaft 10 is rotated in the door opening direction is almost equal to the closing force applied to the door 3 due to the weight of the door 3, the door 3 may be maintained stopped within the opening section.

When the opening angle of the door 3 is less than the predetermined angle, and therefore, the door 3 is placed within the closing section as shown in FIG. 2, the closing guide surface 44 b of the second cam 43 and the closing guide surface 15 b of the first cam 13 are brought into contact with each other, as shown in FIGS. 5 and 8. Therefore, the elasticity of the first elastic member 50 does not affect a rotation of the first hinge shaft 10. Consequently, the first hinge shaft 10 is rotated in the door closing direction due to the weight of the door 3 within the closing section, and therefore, the door 3 is closed.

When the door 3 is closed, a rotation resistance of the second hinge shaft 20 is increased by the damping unit, and therefore, the door 3 is smoothly closed.

More specifically, when door 3, which is in the opened state, is rotated in the door closing direction, the second hinge shaft 20 is rotated, and the second fixing part 103 of the second elastic member 100 is also rotated along with the second hinge shaft 20. When then second hinge shaft 20 is rotated, the second elastic member 100 is twisted while the first fixing part 102 of the second elastic member 100 fixed to the fixing member 80 is maintained fixed. This twisting stress of the second elastic member 100 increases the rotation resistance of the door 3, and therefore, the door 3 is smoothly closed.

When the door 3, which is in the closed state, is rotated in the door opening direction, on the other hand, the second hinge shaft 20 is rotated in the door opening direction by the restoring force of the twisted second elastic member 100, and therefore, the door is easily opened by even a small external force.

As described above, the hinge device 5 according to the present invention includes a singe hinge unit, and therefore, the structure of the hinge device 5 is simplified as compared with the convention hinge device including two hinge units. Consequently, the assembly operation of the hinge device 5 is easily performed. Furthermore, the door 3 is smoothly closed by the shock-absorbing operation of the damping unit, and therefore, an impact force is low when the door 3 is closed.

FIG. 10 is an exploded perspective view illustrating the construction of a damping unit of a hinge device for storage cases according to a second embodiment of the present invention, and FIG. 11 is an exploded perspective view illustrating the construction of the damping unit of the hinge device for storage cases according to the second embodiment of the present invention when a second elastic member is twisted. The hinge device according to the second embodiment is characterized in that the second elastic member comprises a torsion bar 100′, which is made of an elastic material, instead of the torsion spring.

The torsion bar 100′ comprises first and second fixing parts 102′ and 103′ formed at opposite ends thereof such that the first and second fixing parts 102′ and 103′ are fitted into a center of the fixing member 80 and the second hinge shaft 20. Consequently, the guide rod 90 to guide the second elastic member between the second hinge shaft 20 and the fixing member 80 is omitted. Flat surfaces 102′a and 103′ are formed at the first and second fixing parts 102′ and 103′, and first fixing grooves 83′ and second fixing groove 22 b′ are formed at the fixing member 80 and the second hinge shaft 20, respectively, in correspondence to the first and second fixing parts 102′ and 103′ such that the rotation of the torsion bar 100′ relative to the fixing member 80 and the second hinge shaft 20 is prevented, and therefore, the torsion bar 100′ is twisted by the rotation of the second hinge shaft 20.

FIG. 12 is an exploded view, in section, illustrating the structure of a hinge device for storage cases according to a third embodiment of the present invention, and FIG. 13 is a sectional view illustrating the structure of the hinge device for storage cases according to the third embodiment of the present invention.

In the housing 30 is disposed a shaft 200, which extends in the longitudinal direction of the housing 30. Opposite ends of the shaft 200 are fitted in the first and second hinge shafts 10 and 20, respectively.

The cam shaft part 12 is not formed at the first hinge shaft 10, and the first cam 13 is integrally formed at one side surface of the first hinge shaft 10, which is distinguish from the first embodiment. The hinge device according to the third embodiment comprises a supporting member 60′ having no guide 61. At the centers of the first cam 13, a fixing member 80′, and the supporting member 60′ are formed through-holes, through which the shaft 200 is inserted while the guide rod 90 is omitted. Once the shaft 200 is inserted through the centers of the cam driving unit and the damping unit, the components in the housing 30 are stably disposed at the outer circumference of the shaft 200. The shaft 200 inside the first hinge shaft 10 serves as the cam shaft part 12 of the first embodiment to guide the movement of the moving member 40. The shaft 200 inside the second hinge shaft 20 serves as the guide rod 90 of the first embodiment to guide second elastic member 100.

The opposite ends of the shaft 200 may be rotatably fitted in the first and second hinge shafts 10 and 20 or may be fitted in the first and second hinge shafts 10 and 20 while the rotation of the shaft 200 is restricted such that the rotating operation of the door 3 can be uniformly transmitted to the hinge shafts 10 and 20.

Also, at least one space maintaining member 120 is removably disposed at the outer circumference of the shaft 110 between the supporting member 60′ to support one end of the first elastic member 50 and the fixing member 80′ to which one end of the second elastic member 100 is fixed such that the tensions of the first and second elastic members 50 and 100 can be adjusted without changing the lengths of the supporting member 60′ and the fixing member 80′

Although the structures of the hinge devices according to the second and third embodiment are different from that of the hinge device according to the first embodiment, the operations of the hinge devices according to the second and third embodiment are identical to that of the hinge device according to the first embodiment, and therefore, a detailed description thereof will not be given.

As apparent from the above description, the hinge device according to the present invention includes a singe hinge unit, and therefore, the structure of the hinge device is simplified as compared with the convention hinge device including two hinge units. Consequently, the assembly operation of the hinge device is easily performed, and the material costs and the manufacturing costs are reduced. Furthermore, the door is smoothly closed by the shock-absorbing operation of the damping unit, and therefore, the impact force is low when the door 3 is closed.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A hinge device for storage cases to hingedly connect a case body and a door, the hinge device comprising: a housing fixed to one of the case body and the door; first and second hinge shafts rotatably attached to opposite ends of the housing, respectively, wherein the first and second hinge shafts are fixed to the other of the case body and the door; a cam driving unit disposed at the first hinge shaft in the housing; and a torsion spring having one end fixed to the second hinge shaft and the other end fixed in the housing such that a rotation resistance of the door is increased when the door is closed, and the torsion spring is returned to an original state thereof when the door is opened.
 2. The hinge device according to claim 1, wherein the cam driving unit comprises: a first cam disposed at the first hinge shaft; a moving member having a second cam disposed opposite to the first cam; and a compression spring to elastically push the moving member toward the first cam.
 3. The hinge device according to claim 2, wherein the second cam is integrally formed with a side surface of the moving member.
 4. The hinge device according to claim 1, further comprising: a fixing member disposed in the housing at a side of the second hinge shaft, wherein the rotation of the fixing member is prevented, to fix the end of the torsion spring at a side opposite to the second hinge shaft.
 5. A storage case comprising: a case body having a storage compartment opened at the top thereof; a door to open or close a top of the case body; and a hinge device comprising: a housing fixed to one of the case body and the door, first and second hinge shafts rotatably attached to opposite ends of the housing, respectively, wherein the first and second hinge shafts are fixed to the other of the case body and the door, an elastic member having one end fixed to the second hinge shaft and the other end fixed in the housing such that the rotation resistance of the door is increased when the door is closed, and the elastic member is returned to an original state thereof when the door is opened, a connection hole formed at a cover to cover the housing at a side of the second hinge shaft, a rotation preventing pin inserted in the connection hole to prevent rotation of the second hinge shaft, and a catching part formed at the second hinge shaft such that the catching part is caught by the rotating preventing pin to prevent the rotation of the second hinge shaft, wherein the door is attached to the case body while the second hinge shaft is rotated such that the door is closed.
 6. The hinge device according to claim 2, wherein the first and second cams comprise valley-shaped and crest-shaped cam surfaces, the cam surfaces comprising opening guide surfaces formed at an oblique angle and a closing guide surface formed substantially horizontally.
 7. The hinge device according to claim 6, further comprises a leakage preventing member disposed at an outside of the first or second cam to prevent lubricant applied to the respective cam surfaces from leaking out of the cams.
 8. The hinge device according to claim 1, further comprising: a shaft disposed in the housing between the first hinge shaft and the second hinge shaft, the shaft extending in a longitudinal direction of the housing such that opposite ends of the shaft are mounted to the hinge shafts, respectively, the shaft being inserted through the cam driving unit and the torsion spring.
 9. The hinge device according to claim 8, wherein the opposite ends of the shaft are rotatably mounted to the hinge shafts, respectively.
 10. The hinge device according to claim 8, wherein the opposite ends of the shaft are mounted to the hinge shafts, respectively, while the rotation of the shaft is restricted.
 11. A storage case comprising a case body having a storage compartment opened at the top thereof, a door to open or close the top of the case body, and a hinge device to hingedly connect the case body and the door, wherein the hinge device comprises: a housing fixed to one of the case body and the door; first and second hinge shafts rotatably attached to opposite ends of the housing, respectively, wherein the first and second hinge shafts are fixed to the other of the case body and the door; a cam driving unit disposed at the first hinge shaft in the housing; and a torsion spring having one end fixed to the second hinge shaft and the other end fixed in the housing such that a rotation resistance of the door is increased when the door is closed, and the torsion spring is returned to an original state thereof when the door is opened.
 12. The storage case according to claim 11, further comprising: a cam driving unit disposed at the first hinge shaft in the housing, wherein the cam driving unit includes: a first cam disposed at the first hinge shaft; a moving member having a second cam disposed opposite to the first cam; and a compression spring to elastically push the moving member toward the first cam.
 13. The storage case according to claim 11, further comprising: a fixing member disposed in the housing at a side of the second hinge shaft, such that the rotation of the fixing member is prevented, to fix the end of the torsion spring at a side opposite to the second hinge shaft.
 14. A hinge device for storage cases to hingedly connect a case body and a door, the device comprising: a housing; first and second hinge shafts rotatably attached to opposite ends of the housing, respectively; a cam driving unit disposed at the first hinge shaft in the housing; and a damping unit disposed at the second hinge shaft in the housing such that a rotation resistance of the door is increased when the door is closed, wherein the cam driving unit is constructed such that an operating section of the door includes a closing section, within which the door is closed by a weight of the door, and an opening section, within which a rotating force is applied to the first hinge shaft in the door opening direction, and thus, the door is maintained opened, and wherein the damping unit applies the rotating force to the second hinge shaft in the door opening direction such that the second hinge shaft resists the weight of the door throughout the operating section of the door.
 15. The hinge device according to claim 14, wherein the damping unit comprises a torsion spring, the torsion spring having one end fixed to the second hinge shaft and the other end fixed in the housing.
 16. The hinge device according to claim 14, wherein if the door is opened more than a predetermined angle, the rotating force in the opening direction is applied to the first hinge shaft and the door remains opened, and if the door is opened less than the predetermined angle, the first hinge shaft is rotated in a door closing direction by the weight of the door.
 17. The hinge device of according to claim 14, wherein the damping unit comprises a torsion bar, the torsion bar having one end fixed to the second hinge shaft and the other end fixed in the housing.
 18. The hinge device according to claim 17, further comprising: a fixing member disposed in the housing at a side of the second hinge shaft, such that a rotation of the fixing member is prevented, to fix the end of the torsion bar at the side opposite to the second hinge shaft.
 19. The hinge device according to claim 18, wherein the torsion bar comprises first and second fixing parts formed at opposite ends thereof such that the first and second fixing parts are fitted into a center of the fixing member and the second hinge shaft, respectively.
 20. The hinge device according to claim 19, wherein the first and second fixing parts each comprise flat surfaces, and the fixing member and the second housing comprise first and second fixing grooves, corresponding respectively to the flat surfaces of the first and second fixing parts, such that a rotation of the torsion bar relative to the fixing member and the second hinge shaft is prevented and the torsion bar is twisted by a rotation of the second hinge shaft. 